The use of smart labels that can be placed on top of unit dose medication blisters are known in the art and described in WO 2008000479 (A1) and WO 2007077224 (A2).
The first document discloses a label which notes the manipulation of objects which it labels by generating an altered electrical signature is provided. The label comprising a stack of layers and an adhesive coating, the stack of layers comprising first, second and third layers, the first and third layers each comprising flexible, conformable, electrically conductive or semiconductive material and each comprising an electrical contact point for connection into an electrical circuit, the second layer comprising a flexible, deformable and compressible material, said second layer being electrically nonconductive or electrically conductive but less conductive than the first and third layers, said second layer separating said first and third layers, with the adhesive coating being suitable for attaching the stack of layers to the object.
WO 2007077224 teaches how to build improved systems for monitoring patient compliance with medication regimens. The systems note when unit doses of medication are dispensed to a patient and include a detector for generating a signal each time a unit dose is dispensed as well as a signal processor which can act upon the signal. The devices include a flexible conductive substrate physically supporting and connecting the detector and the processor into a unitary structure and conducting the signal from the detector to the processor. In embodiments the flexible conductive substrate employs flexible conductive organic materials.
The basics of touch pads are also very well known in the art and described for example in U.S. Pat. Nos. 3,662,105 and 3,798,370. The first document discloses an inexpensive electrical sensor of plane coordinates that employs juxtaposed sheets of conducting material having electrical equipotential lines extending across each sheet and arranged normal to each other. A probe upon touching each sheet at a selected intersection of the equipotential lines causes separate signals to be applied to one or more conventional information-indicating units.